Measurement equivalence of neuropsychological tests across education levels in older adults.

OBJECTIVE: The objective was to determine whether neuropsychological tests provide an equivalent measure of the same psychological constructs in older adults with low versus higher levels of education. METHOD: Confirmatory factor analysis was used to evaluate the fit of a three-factor model (Verbal Ability, Visuospatial Ability, Long-Term Retention) to scores from the neuropsychological battery of the Canadian Study of Health and Aging (CSHA). Measurement equivalence of the model across lower educated (LE; ≤8 years) and higher educated (HE; ≥9 years) participants was evaluated using invariance testing. RESULTS: The measurement model demonstrated adequate fit across LE and HE samples but the loadings of the 11 tests onto the three factors could not be constrained equally across groups. Animal Fluency and the Token Test were identified as noninvariant tests of Verbal Ability that, when freed from constraints, produced a partial metric invariance model. Scalar invariance testing identified the Buschke Cued Recall Test and Block Design as measures with invariant factor loadings but noninvariant intercepts. Analyses were replicated in age- and sex-matched subsamples. CONCLUSIONS: Metric and scalar invariance across HE and LE samples was achieved for seven of the 11 tests in the CSHA battery. Animal Fluency and the Token Test were noninvariant measures of Verbal Ability, suggesting that cognitive processes underlying performance on these tests may vary as a function of education. In addition, scores from Block Design and the Buschke Cued Recall Test were observed to differ in their scale of measurement between HE and LE examinees.